JPH02276136A - magnetron - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to magnetrons.

[Conventional technology]

Figure 3 shows an example of a conventional magnetron, in which both ends of the filament 1 are supported by filament supports 4 and 5 via an end shield 2.3, and the filament support 4.5 forms a vacuum vessel. It penetrates the insulator 6 and is brazed to the insulator 6 via a metal washer 7. Further, an anode consisting of a plurality of radially arranged vanes 8 and an anode cylinder 9 for holding them is disposed around the filament 1. Every other vane 8 is electrically connected by a strap ring 10.11. An output conductor 12 is connected to one of the vanes 8 so that microwave energy generated in one working space is radiated to a load circuit through an output radiation window 13.

Further, magnetic poles 14.15 for supplying a focused magnetic field to the working space are fixed to the upper and lower ends of the anode cylinder 9, and magnetic poles 14.15 are further fixed to the upper and lower ends of the anode cylinder 9.
15 respectively output radiation windows 1 via rings 16 and 17.
3. The insulator 6 is soldered and sealed to form a vacuum container.

The above conventional example is 1, for example, Japanese Patent Application Laid-Open No. 53-90752.
It is described in etc.

By the way, the filament 1 is made of thorium-containing tungsten with a carbonized surface layer because it is easy to obtain stable electron emission, and the operating temperature is 1700-1800.
The temperature is 00°C. Therefore, the end shield 2.3 supporting the filament 1 and the filament support 4
．． 5 must also be made of a material that can be used at high temperatures, and molybdenum (Mo) is generally used. Furthermore, since it is difficult to reliably seal the filament support 4.5 made of Mo to the insulator 6 made of ceramic by brazing, the metal washer 7 is made of Kovar, which has an expansion coefficient close to that of the ceramic insulator. (Fe
-Ni-Co alloy) is used.

[Problem to be solved by the invention]

In this way, since the filament support 4.5 is formed long enough to penetrate the insulator 6, M.

Requires a large amount of expensive high-melting point metals such as Also Mo
has poor wettability with silver solder, making reliable brazing difficult. Furthermore, since Mo is a brittle material, defects are likely to occur on the surface and inside when it is processed into rods or wires.If the filament support 4.5 penetrates inside and outside the vacuum container as described above, the defects will cause the vacuum to fail. Leakage is likely to occur, and the metal washer 7 must be made of an expensive and uncommon metal such as Fe-N1-Go.

Furthermore, since the insulator 6 and the washer 7, and the washer 7 and the filament support 4.5 are each soldered with silver,
This method has various drawbacks, such as requiring a large amount of expensive silver brazing material, complicating the sealing structure, and being susceptible to vacuum leaks.

Another problem with the prior art is the sealing surface between the ring 17 forming the metal envelope and the insulator 6.

Since the sealing surfaces of the filament support 4 and the insulator are formed on different sides of the insulator, the process of pre-treating the insulator for sealing becomes complicated, increasing manufacturing costs. There was a problem.

The present invention was made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide an economical and highly reliable magnetron.

tim1 problem] In order to improve the reliability of the sealing part between the filament support 4゜5 and the insulator 6, which is the first am, the filament and connection.

This problem can be solved by sealing this auxiliary sealing material and the insulator 6.

This is the second 11 questions. Since the sealing surfaces are formed on both sides of the insulator 6, the problem that the pretreatment for sealing with metal must be performed on both sides of the insulator is solved by the filament support. Alternatively, the problem can be solved by forming the sealing surface between the auxiliary sealing body and the insulator inside the vacuum container.

[Effect]

Since the auxiliary sealing body used to solve the first problem is not limited to heat-resistant metal materials, it is possible to select a material that has good sealing properties with the insulator, thereby increasing the reliability of the sealing part. can.

゛If the above-mentioned means for solving the second problem is used, the sealing surface between the filament support or the auxiliary sealing body and the insulating material can be bonded to the metal constituting the vacuum envelope and the insulating material. It can be formed on the same side as the sealing surface.

The present invention will be explained below with reference to illustrated embodiments.

【Example〕

FIG. 1 is a sectional view showing an embodiment of the magnetron according to the present invention. Note that the same members as in FIG. 3 are given the same reference numerals and their explanations will be omitted. Filament support 20.
21 is formed to a short length that does not penetrate the ceramic insulator 6, and an auxiliary sealing body 22 made of Fe material that penetrates the insulator 6 is attached to the end of this filament support 20.21 by plasma welding, butt resistance welding, etc. It is fixed by. A flange portion 22a is formed on the auxiliary sealing body 22, and a cup-shaped portion 22b having a thin wall of about 0.41 mm on the surface corresponding to the insulator 6 is formed on the flange portion 22a by integral plastic processing. has been done.

The tip of the cup-shaped portion 22b is brazed to the metallized alumina ceramic insulator 6.

Now, the operating temperature of the filament 1 is high, but the filament supports 20 and 21 have a temperature gradient that decreases toward the outside of the tube, and the temperature near the insulator 6 is sufficiently low, so the auxiliary sealing As the material of the body 22, a metal with a low melting point such as Fe can be used. Furthermore, although the expansion coefficients are different between the ceramic insulator 6 and the auxiliary sealing body 22 made of Fe, the sealing portion of the auxiliary sealing body 22 is
2b allows stress relaxation by plasticity.

In this way, the filament supports 20.21 are of a short length that does not penetrate the insulation 6.

Since the auxiliary sealing body 22 is made of inexpensive iron, it is possible to reduce the amount of expensive high-melting point metal such as Mo used, so it can be integrally processed into a shape that is easy to plastically work and is easy to seal. , the expensive and high melting point washer 7 in FIG.
can be omitted.

It has better ductility and malleability than MO, does not produce defects on the surface or inside during processing, and improves the reliability of vacuum sealing. Furthermore, the filament supports 20, 21 and the auxiliary sealing body 22 can be fixed together by welding or the like, which is an easy operation and does not require an expensive brazing material.

FIG. 2 is a sectional view of a main part showing a second embodiment of the magnetron according to the present invention. In the previous embodiment, the auxiliary sealing body 22 was sealed on the outside of the insulator 6, but in this embodiment, it was sealed on the inside. In this way, it becomes possible to seal the auxiliary sealing body 22 and the ring 17 on the same side with respect to the insulator 6.

Therefore, the pretreatment process performed on the insulator 6 for sealing the insulator and metal can be simplified. Further, as shown in FIG. 2, if the auxiliary sealing body 22 and the ring 17 are formed on the same plane with respect to the insulating material, the pretreatment process can be further simplified.

The above description has been made assuming that the auxiliary sealing body and the insulating material are sealed together, but the same effect can be obtained when the filament support and the insulating material are sealed as before without using the auxiliary sealing body. Of course, it is necessary to have one.

In the above embodiment, the material of the auxiliary sealing body 22 is F.
Although we have explained the case of e, there is no particular limitation as long as it is a metal with a melting point lower than that of Mo and can withstand the temperature around the insulator 6. For example, it may be an Fe-Ni alloy. If the expansion coefficient with the body 6 is large, the thin cup-shaped portion 22b is attached to the auxiliary sealing body 22 as described above.
However, when an Fe-Ni alloy is used for the auxiliary sealing body 22, the cup-shaped portion 22b is not provided and the flat flange portion 22a is used.
In the above embodiment, the filament 1 is supported by the filament supports 4 and 5 via the end shield 2.3, but the tip of the filament support is The filament may be supported directly by the bent portion.

〔Effect of the invention〕

According to the present invention, it is possible to manufacture a magnetron whose sealing portion has high reliability and whose manufacturing cost is low.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the magnetron according to the present invention, Fig. 2 is a sectional view showing main parts of another embodiment of the magnetron according to the invention, and Fig. 3 is a sectional view of a conventional magnetron. be. 1... Filament, 2.3... End shield,
6... Insulator, 17... Ring, 20.21...
Filament support, 22... Auxiliary sealing body, 22a
...Flange part, 22b...Fig. Fig. Fig.

Claims (1)

[Claims] 1. The vacuum container is composed of at least a metal and an insulator, the insulator and the metal layer are sealed at a first sealing surface, and both ends of the filament constituting the cathode are In a magnetron supported via an end shield or directly by a filament support, the filament support or an auxiliary sealing body connected to the filament support is sealed to the insulator at a second sealing surface. . A magnetron, wherein the first sealing surface and the second sealing surface are formed on the same side of the insulator. 2. The magnetron according to claim 1, wherein the first sealing surface and the second sealing surface are formed on the same plane of the insulator. 3. The magnetron according to claim 1 and claim 2, wherein the second sealing surface is formed inside a vacuum container.